Maliks Muwatta Book 9, Hadith Number 57.
Section : Waiting for The Prayer and Walking to It.
Yahya related to me from Malik from Nuaym ibn Abdullah al-Mujmir that he heard Abu Hurayra say, “If any one of you prays and then sits down in the spot where he has prayed, the angels ask blessings on him saying, ‘Allah, forgive him. Allah, have mercy on him.’ And if he moves from the spot where he has prayed and sits elsewhere in the mosque waiting for the prayer, he remains in prayer until he prays.”